I don't want a laundry tub - can I use a sink instead?

This one comes up a lot. Can a sink be used instead of a laundry tub? Space is limited in modern developments, so laundries are often combined with kitchens or bathrooms, and to save more space, people are asking us if they can do away with the laundry tub.

Yes or no? Well, to answer this one, we have to go back to the performance requirements and see what the NCC requires for facilities and personal hygiene. For Class 2 buildings and Class 4 parts of buildings, so dwelling sole occ units, the performance requirements simply requires that facilities or a space for laundry, including a convenient way of getting rid of waste water be provided.

The same goes for Class 1 buildings. Now, we have here in Volume Two some explanatory information which highlights that we need a way of getting rid of the waste water that comes from domestic cleaning processes, like the water in your mop bucket or the water that you soak your dirty socks in. And there's a very similar line in the Guide to Volume One, to this explanatory information box, which comments on FP2.2, the forms required that we just looked at on the previous slide. Note carefully, these are the performance requirements.

They're not optional. You need to have a way of emptying a bucket of dirty water in a home or in an apartment. This is how the Deemed-to-Satisfy Provisions achieve these performance requirements in Volume One for Class 2 buildings and Class 4 parts of buildings. You need to have your facilities, including at least one washtub, and in case there was any doubt, (a)(iii) here states that a kitchen sink or a washbasin cannot be counted as a laundry washtub.

It's the same in Volume Two. You need at least one washtub, and as per the explanatory information, as far as we're concerned, the only thing you can empty your mop bucket into is a laundry tub. So, no, under Deemed-to-Satisfy, you cannot use the sink instead of a washtub, and performance requirements say you need to have a washtub.

But there is related question that I'm sure somebody has thought of already, and that person's thinking, I won't use the sink as the laundry tub. What if I use the laundry tub as the sink? Clever, isn't it? I admit that this one's down to judgement, but my judgement on this one is that under Deemed-to-Satisfy, and answer is still no, and that's because the Deemed-to-Satisfy is listing separate things. You need each of the things listed, a handwashing sink and a kitchen sink and a laundry tub. That's a list of three things.

So when I'm doing my final inspection, I want to see three things. If the Deemed-to-Satisfy Provisions were inviting us to apply judgement, it would use less prescriptive language, such as telling us provide a means of disposing of waste water. But of course, this a performance-based code, and you're certainly welcome to use performance and just remember that the performance requirements are looking for a hygienic way of getting rid of dirty water, if you do choose to apply a performance solution. It's not very hygienic to rinse your vegetables in the same sink that you soak your dirty socks in or empty your mop bucket into.

So please do not try and combine your laundry tub with your kitchen sink. Do I have to waterproof the laundry tub splashback? This bit highlighted by the red arrow. Yes or no? Well, let's have a look. You're not going to find the term splashback in the BCA. The BCA is referring to this bit as a wall adjoining a vessel.

This is Table 3.8.1.1 in Volume Two. In Volume One, it's Table F1.7. It's the same in both volumes, and for a sink, basin or laundry tub, you only need to achieve a water resistant finish, for at least 150 millimetres above the vessel if that vessel is within 75 millimetres of the wall. Not waterproof. So tiles without a waterproofing membrane is okay, though do note, if you fix your vessel to the wall, then you must waterproof the junction, and in accordance with AS 3740, a bead of sealant will achieve this waterproof junction. So we only need to achieve a water resistant splashback, and the wall vessel junction must be waterproof where we've fixed the vessel to the wall. So the answer to this question, no waterproofing is required, tiles are okay.